Many of the ingredients commonly used in soil mixes in the US and Europe are either not availavle or very expensive. These include vermiculite, perlite and peat moss. Pumis is available but we have not tried it yet.
The most available materials are rice hulls and coir. So far we have had success with them by mixing to suit the drainage and root aeration requirements of the plant. For succulents I have tried compositions varying between 100% rice hulls and 50% rice hulls, depending on the species of interest. For rooting cuttings 100% rice hull has worked well.
Some things I have read about coir suggest that the salt content, its binding capacity for magnesium and initial nitrogen requirements may be problematic. Coir (shredded coconut hulls) produced in Colombia appears to have less salt than Asian products and works very well for most plants. For plants which may be very sensitive to salt such as seedlings, I triple soak the coir to rinse out the salt. In general I add a nitrate nitrogen fertilizer and Epsom Salts in the final rinse. The Epsom Salts handles any potential magnesium deficiency. This strategy has worked very well. The magnesium also helps flush out salt. We have had good results using coir chips for orchids.
Based on some work with gesneriad seedlings access to inexpensive peat moss would be a benefit. So far the other materials we have problems getting here don’t seem to be critical. More as time goes by and experience is gained.